1. Field of the Invention
The present invention relates to solids separation devices and, more particularly, to an apparatus which distributes the flow of solids to two or more solid separation devices.
2. Setting of the Invention
In the technology of separating entrained solids from liquids, it is well known to use solid separation devices such as desilters, desanders, hydrocyclones, centrifuges and especially shale shakers. Generally, shale shakers are devices that operate by passing a mixture of solids and liquid onto a vibrating screen. The motion of the vibrating screen causes fine solids and liquid to pass through the screens and passed on downstream for further processing, if desired. The solids that cannot pass through the screen are transported there across to a discard zone. In the event that two or more solid separation devices are utilized in parallel, the usual arrangement for the distribution of the inlet flow of solids and liquid to such solids control devices is as shown in FIG. 1. As can be seen in FIG. 1, a simple Y, T, or elbow connection is made from a main conduit to direct the flow of solids and liquid to inlet zones of the shale shakers. This arrangement has a major problem in that the proportion of solids provided to each of the shale shakers is not regulated, so that one shale shaker may be overburdened so that the separation efficiency decreases as the screens become clogged. Even using valves on each inlet flow conduit does not regulate the quantity and proportion of the solids that are passed to each shale shaker.
There is a need for a reliable mechanism for regulating the proportion of solids that is provided to each solid separation device.
In prior shale shakers, the flow of solids and liquid passes first into an accumulation zone, usually called a "mud box" and shown in FIG. 1A. This mud box serves as a location for electronic sensing equipment to be positioned, such as a mud gas detector and other mud sensor instrumentation. The larger solids tend to lose their mobility in this accumulation zone and begin to fill the mud box. When the shale shaker's screens are changed, a dump valve located near the bottom of the mud box is opened and these larger solids, as well as the total flow of solids and liquid are passed downstream where they become remixed with "clean" fluid. It is well known that such larger solids clog downstream solid separation equipment, especially hydrocyclones. Further, the accumulation of larger solids in the mud box must be removed periodically. Usually, a lower trap door is opened or an operator must shovel the solids out. In either case, a considerable loss of expensive drilling fluids occurs.
There is a need for a solids separation device which can eliminate the need for a solids accumulation zone, or at least prevent separated larger cuttings from reentering the solids separation flow.